Process for the manufacture of metallic sheets



Aug. 11, 1931. J, R, CAIN ET AL h 1,818,379

PROCESS FOR THE MANUFACTURE OF vMETALLIC SHEETS Filed. Dec. 2, 1927 INVENTOR. Jwm BY l v I TTORNEYS Patented Aug. l1, 1931 `v UNITED As'rA'rr-:s

.PATENT ori-Ica JOHN R. GAIN, OF WASHINGTON, DISTRICT OF COLUMBIA, AND GIBSON YUNGBLUT, OF DAYTON, KENTUCKY, ASSIGNORS'TO THE RICHARDSON COMPANY, OF LOCKLAND,

OHIO, A CORPORATION OF OHIO PROOES FOR THE MANUFACTURE OF METALLIC SHEETS Application filed December 2, 1927. Serial No. 237,295.

Our invention has to do with processes of forming metallic sheets directly by electroly'tic means. In such processes metallic sheets are deposited from a suitable electrolyte by the action of an electric current, -upon a conducting surface which forms the cathode of an electrolytic cell. A number of such processes have been proposed and some of them are in practical operation.

The deposition of metal upon a rotatmg cylindrical cathode from which the deposit is continuously stripped, has been proposed. Electrolytic sheet copper is made to-day by electrodepositing copper upon prepared cathode blanks the. surfaces of which have been sulphided-or otherwise treated so that the deposit may be more or less readily removed therefrom. v

` In the manufacture of thin sheets or foils, articular-ly ofthe precious metals, it has geen proposed to plate the precious metal upon a cathode blank `of base metal, which may bein lthe form of a sheet or strip or the like, and subsequently to remove the base metal from the precious metal by the use of a chemical reagent which will selectively at tack it.

All of these processes, however, involve either a mechanical stripping, which is cumbersome, expensive and uncertaimor a chemical stripping which results in the destruc tion of the cathode blank. l y

`In application iled on August 19th, 1927, by the present applicants, Serlal No. 214,194, the method of forming electrolytic sheets is set forth, wherein a rollingr or elongating step is relied upon to increase the cathode area so as to produce not only a finished or semii, to an outside source of supply forcathodel finished end product of the operation, but also a piece which will serveas the cathode in a continuation of the process.

It is the object of the present invention to utilize in a bimetallic sheet-forming operation a-method of continuously regenerating the cathode blanks so that the process becomes a continuous one and is notsubject blanks.l We accomplish our object by that certain series of steps which will be hereinafter speciically pointed out in a typical example, and in which the inherent novelty will be set forth in the claims that follow.

Referring to the drawings Figure 1 is diagrammatic inasmuch as the mechanisms by which the several steps are -accomplished are well known to those skilled blank 1, and the anode C may advantageously contain the same metal as that which the electrolyte contains, though insoluble anodes may i of course be used in the process. The action of a' source of electrical energy D connected to the anode and the cathode blank is to cause a deposit of metal 2 to be laid down upon the cathode blank 1.

We continue the electrolytic action in the cell A until the thickness of the deposited metal sheet is also twice that required in the finished product.

, The bimetallic article 1-2 is now removed from the electrolytic bath, washed as at F and subjected to one or more passes through a rolling mill E, with such intervening annealings as may be required by the nature of the metals and the amount of reduction contemplated. In this rolling operation we reduce the metallic composite 1-2 at least to one-half its thickness, and we may,if desired,

reduce it further, as will be apparent later. In this rolling operation the length will obviously be at least doubled.

We next sever as by shear G the rolled metallic article into two parts (assuming Vthat we have doubled its length and decreased its thickness by one-half), and we designate the t'wo parts thus formed as portions la-Qa and lb-Qb. Both of these bimetallic articles lare placed in an electrolytic stripping cell H containing as an electrolyte a solution of a etl salt of the metal 1, of such, characteristics that under electrolytic conditions the metal dissolved at the anode anode and the other the cathode, facing metal portions 1a and 1b toward each other, and utilize through suitable connection .a` source of electrical energy indicated at I.- The result of the electrolytic action will be to dislo solve the metal from one bimetallic article,

and to deposit an equivalent amount of metal upon the other bimetallic article which we have made the cathode of the couple.

The end product of the anode in this electrolytic process will be a nished sheet of metal 2. This finished sheet will be of the re' quired or single thickness. The end product of the cathode in the cell H will be a bimetallic article consisting of a sin 1e thickness of the metal 2 and a double t ickne'ss'of the metal 1, and we have designated this at 4. It

' will be obvious that this can be returned tc process thickness, which may the electrolytic cell A to receive a further deposit of the metal 2 and the process will thus be continuous and precisely identical with the steps hitherto described except that the action of the electric current in the cell A needxbe continued only long enough to deposit a single thickness, of the metal 2 on the composite blank 4, since one thicknessis there already.

We will now give as a ty vical exam le a process` of manufacturing t in iron s` eets upon a prepared cathode blank of copper. We start asabove indicated with a cop er Acathode'blank which will be a smooth ro ed sheet of soft copper of the size of the required inished iron sheet and of a convenient be .04. Our electrolyte in the electrolytic cell A will be a hot neutral ferrous chloride electrolyte containing approximately 100 'grams metallic iron Eer liter, and the 4`electrolytic w ich we propose., vto -use is to employA an anode formed of iron sulphide to ther with other conditioning means, and

` a ltration system fonthe electrolyte which Uso keepls down hydrogen ion concentration to a neg 'gble amount, and keeps the electrolyte free from sediment.

The result of this practiceis to keepv the said bath in condition so that the iron elec-u trodeposited therefrom will. be soft, malleable and ductile, and if the currentdensity is maintainedat the proper values, of a fine grained nature.

Through theA action of a suitable source of electrical energy we deposit iron upon the copper cathode blank until its thickness vis f .04 or somewhat greater. The resultant bi1 metallic article. will therefore be .08" in thickness or thereabouts'.

We then remove it from the bath and after washing pass it through cold rolls until its length is doubled and its thickness again reoil heated to aboutv 400`centi duced to .04. The product after rolling will consist therefore of a layer of copper .02

in thickii'ess and a layer `of iron also .02 in thickness. lThe softness of the iron deposited -skilled operator to perform; but inasmuch as the copper, upon rolling, tends toharden up much @more rapidly than the iron, it is 'frequently possible to use in an annealing step a temperature such as will anneal the copper and not the iron, or anneal the co per more than the iron. We have thus foun it possible to use in annealing a bath of hydrocarbon ade, through which the strip is passed slow y, or in which it is submerged in any` desired .vvay, which will soften the copper without oxidizing and with a reducing action leaving the surface bright, but will have very little eifectupon the iron. It will be further obvious that in connection with the rolling operation the opf erator willdo such trimming of the metallic com osite as may be necessaryv and that the thic ess of the various, depositswillhave to take into account any necessary trim.

We next sever our `com osite article into two parts and place them oth in anv electro-I lytic cell H containing a solution of cyani e' susioo

of cop er. Two bimetallic' ieces are placed in the ath with the copper aces toward each other. One of them is made the anode and the other the cathode, and suitable connections made to a source of electrical ener under the action of which the copper wi Abe dissolved from the face of the iron on the anode and deposited upon the copper face of Y the cathode.

.At the-end of the electrolytic stripping operation the anode will consist of the ,finished iroifsheet .02" in thickness, one face of which will have been electrode osited a ainst a..l rolled face of the copper b ank and t e other face of which will have been rolled in the roll in operation described above, and also trimmed. It therefore will be a smooth and polished finished article on both sides.

The cathode blank removed from the stripping cell will consist of a. double thickne of cop r and a' singles thickness of iron. After was in it may transferred directl back to the e ectrolytic cell A for a further eposit of iron on the iron face thereof, although if desired, it may be passed through cold rolls:

before being returned to the ferrous chlorideelectrolytic cell.

A sired area i Having thus described our invention, what we claim as new and desire to secure by Letthe original cathode, thus forming a new'l cathode having ori '-nal thickness of the cathode metal and ha f of the plated thickness of the same metal as the metallic object, and then platingr on the new cathode with the metal of the object to form a new blank for elongating, for the purpose described.

2. That process of forming electrolytic metal sheets, which consists in platin a desired metal on a cathode sheet, elongating the sheetv to at' least twicer its original length, severing the cathode to form a sheet of the deplatin'g the cathode metal from the severe ody back onto the cathode metal 'of' the remainder of the elongated cathode,

thus makinga new cathode, and then plating the desired metal onto the portion of the new cathode blank which is of that metal, for the purpose described.

3. That process of forming electrolytic metal sheets, which consists in plating a desired metal on a cathode sheet, elongatmg the sheet to at least twice its original length, severing the cathode to form a sheet of the desired area, plating the cathode metal from the severed body back onto the cathode metal of the remainder of the elongated cathode, thus making a new cathode, and then lating the desired metal onto the portion of t e new cathode blank which is of thatmetal, for

onto a piece ofthe same shape as the piece to be stripped, and employing said iece onto which the second plating is ap lie as cathode material in a subsequent p ating xopera-` v tion.

7, That process of forming electrolytic metal sheets, which consists in plating the metal on a starting sheet of another metal, working the comlposite sheet thus roduced and electrolytica y stripping the ot er metal from the sheet by plating it onto a piece of metal which is the resultfof a working of a sheet such as the starting sheet, and using said secondly plated sheet asa cathode for a second plating operation.

8. That process of forming electrolytic iron pieces, which consists in onto a piece of copper, working t piece t away from the plated piece y p ting `o the copper onto a piece of copper and employing said piece of copper in a subsequent plating operation. f. .n JOHNRCAIN. Y

' GIBSQN YUNGBLUT.

e composite "the pur ose described, said elongatiiigl being acccmp ished bycold rolling. 4. That recess of forming foils, whic consists in plating iron onto a cop r sheet, cold rollin the plated body and cutting from it a piece a desired area, plat- -ing the copper from the severed piece back ,onto the cop r of the remainder ofthe elonated cath e blank making a new cathode,

t en plating iron on the iron portion of the new cathode, for the purpose described.

5. That process of forx'nm electrolytic iron sheets, which consists in p ating iron on asheet of another metal, elongating the composite sheet, electrolytically stripping the other metal from the iron by plating it onto iron sheets or a strip of metal and employing said strip of metal as cathode material in a subsequent platin operation.

6. 'Iiat process of metal on a piece of another metal. which is alike-in shape to the product to beiproduced working the com ite piece thus formed an stripping the ot er metal o by plating it forming electrolytic metal pieces, which consists in platin saidplating iron` us formed and stri pingthe co per 

